Currently, in a small camera of a mobile phone and the like, a small shooting lens having lenses whose number is reduced to three to four is used. In recent years, in order to reduce the number of lenses on one hand and to improve imaging quality (especially to correct chromatic aberration) on the other, there has been proposed a technique of combining a diffractive optical element with a shooting lens (see Patent Document 1 and so on).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2005-301048